The sound of Barack Obama's radio ads sometimes depends on where the listener lives.
In Iowa, Obama's ad features the state fair's "Butter Cow Lady," and is set to country music. In South Carolina, his ads have a rhythm and blues soundtrack, as they tell the Illinois senator's personal story and how, as a young boy, he was raised by a single mother.
Obama is not alone in targeting his advertisements to fit his geographic audience.
Many of the presidential candidates are running ads, designed to appeal to voters in one region of the country or members of special demographics.
Republican candidates have been burning up the airwaves of the Des Moines Christian Rock Station KZZQ. Station manager Eric Boatright says no Democratic candidates have signed up for airtime.
Both Republican and Democratic candidates are running radio ads on Spanish-language stations in some of the early primary states.
New York Sen. Hillary Clinton's ads tell Latino voters that they could influence the outcome of the caucuses, while Obama's ads highlight the fact that his father was a foreigner who came to the U.S. looking for a better life. None of the advertisements touch on the lightning rod issue of immigration.
An editor at the Hispanic political Web site Candidato U.S.A., Luis Clemens, says the candidates can't afford to get too specific in Spanish advertisements.
"The days when you could hide your Hispanic political marketing efforts under a bushel are gone," he said. "Everyone's going to be able to find out about it and translate those ads very quickly."
But Clemens says the candidates don't really need to make specific promises in the ads; just the sound of the candidates communicating in Spanish — as former Massachusetts Gov. Mitt Romney (R) does in one ad, saying "I approve this message" in Spanish — is in itself a powerful message.